Overview
- The peer-reviewed analysis in BMC Cardiovascular Disorders, covered widely Tuesday, tracked 3,231 Finnish adults for about 10 years using one week of wearable sleep data.
- Large swings from night to night in bedtime or in the sleep midpoint were tied to nearly double the rate of major events such as heart attack, stroke, heart-failure hospitalization, unstable angina, or cardiovascular death.
- The association appeared only in participants averaging under the cohort median of roughly 7 hours 56 minutes in bed, with no added risk seen among longer sleepers.
- Variability in wake-up time alone did not predict higher risk, pointing to bedtime consistency as the more actionable habit.
- Researchers adjusted for blood pressure, LDL cholesterol, BMI, A1c, employment, and physical activity, yet they caution that seven baseline nights and 128 events limit causal claims and that larger, more diverse studies are needed.